AM Bench 2022 Macroscale Tensile Challenge at Different Orientations (CHAL-AMB2022-04-MaTTO) and Summary of Predictions.

The additive manufacturing benchmarking challenge described in this work was aimed at the prediction of average stress-strain properties for tensile specimens that were excised from blocks of non-heat-treated IN625 manufactured by laser powder bed fusion. Two different laser scan strategies were considered: an X-only raster and an XY raster, which involved a 90° rotation in the scan direction between subsequent layers. To measure anisotropy, multiple tensile orientations with respect to the build direction were investigated (e.g., parallel, perpendicular, and intervals in between). Benchmark participants were provided grain structure information via electron backscatter diffraction measurements, as well as the stress-strain response for tensile specimens manufactured parallel to the build direction and produced by the XY scan strategy. Then, participants were asked to predict tensile properties, like the ultimate tensile strength, for the remaining specimens and orientations. Interestingly, the measured mechanical properties did not vary linearly as a function of tensile orientation. Moreover, specimens manufactured with the XY scan strategy exhibited greater yield strength than those corresponding to the X-only scan strategy, regardless of orientation. The benchmark data has been made publicly available for anyone that is interested [1]. For the modeling aspect of the challenge, five teams participated in this benchmark. While most of the models incorporated a crystal plasticity framework, one team chose to use a more semi-empirical approach, and to great success. However, no team excelled at all the predictions, and all teams were seemingly challenged with the predictions associated with the X-only scan strategy.

Effects of SARPE and MISMARPE on correction of transverse maxillary deficiency: A preliminary comparative evaluation.

AIM: The present study was designed to compare, on cone-beam computed tomography imaging, the skeletal and dental effects of the SARPE (Surgically assisted rapid palatal expansion) and MISMARPE (Minimally Invasive Surgical and Miniscrew-Assisted Rapid Palatal Expansion) techniques. MATERIALS AND METHODS: The sample of adult patients with transverse maxillary deficiency (TMD) was divided into two groups, and scans were obtained preoperatively (T0) and immediately after completion of expansion (T1). The posterior and anterior linear transverse distances of the maxilla and the angulation of the maxillary first molars were evaluated. The data were entered into a generalized estimating equations model to verify the postoperative effects of the different techniques. RESULTS: None of the techniques caused any appreciable change in the angulation of the molars. The skeletal changes were similar, with significantly greater gains in the nasal fossa and intermaxillary distance when using the MISMARPE. CONCLUSION: The technique can be an effective and lower morbidity alternative to SARPE.

Unintended consequences: Assessing thermo-mechanical changes in vinyl nitrile foam due to micro-computed X-ray tomographic imaging.

Micro-computed X-ray tomography (µCT) is a volumetric imaging tool used to quantify the internal structure of materials. µCT imaging with mechanical testing (in situ µCT) helps visualize strain-induced structural changes and develop structure-property relationships. However, the effects on thermophysical properties of radiation exposure during in situ µCT imaging are seldom addressed, despite potential radiation sensitivity in elastomers. This work quantifies the radiation dosage effect on thermo-, chemical-, and mechanical-properties for a vinyl nitrile-based foam. Material properties were measured after (0, 1, 2, and 3) days at (8.1 ± 0.9) kGy/d. Morphological characteristics were investigated via scanning electron microscopy. Thermal transitions were assessed using differential scanning calorimetry. Viscoelasticity was measured with dynamic mechanical analysis over a range from -30 °C to 60 °C. Higher dose lead to stiffening and increased dissipation. Chemical structure was assessed with Fourier transform infrared spectroscopy and energy-dispersive X-ray spectroscopy. Soxhlet extraction was used to measure gel content. In summary, substantial changes occur in thermophysical properties, which may confound structure-property measurements. However, this also provides a modification pathway. Quantitation and calibration of the properties changes informed a finite element user material for material designers to explore tunablity and design optimization for impact protection engineers.

A materials data framework and dataset for elastomeric foam impact mitigating materials.

The availability of materials data for impact-mitigating materials has lagged behind applications-based data. For example, data describing on-field helmeted impacts are available, whereas material behaviors for the constituent impact-mitigating materials used in helmet designs lack open datasets. Here, we describe a new FAIR (findable, accessible, interoperable, reusable) data framework with structural and mechanical response data for one example elastic impact protection foam. The continuum-scale behavior of foams emerges from the interplay of polymer properties, internal gas, and geometric structure. This behavior is rate and temperature sensitive, therefore, describing structure-property characteristics requires data collected across several types of instruments. Data included are from structure imaging via micro-computed tomography, finite deformation mechanical measurements from universal test systems with full-field displacement and strain, and visco-thermo-elastic properties from dynamic mechanical analysis. These data facilitate modeling and design efforts in foam mechanics, e.g., homogenization, direct numerical simulation, or phenomenological fitting. The data framework is implemented using data services and software from the Materials Data Facility of the Center for Hierarchical Materials Design.

Fat grafting in patients with cleft lip and palate: A systematic review.

This systematic review aims to compare different fat-grafting techniques for cleft lip and palate repair. A search was conducted in PubMed, Embase, Cochrane Library, gray literature and reference lists of selected articles. A total of 25 articles were included, 12 on closure of palatal fistula and 13 on cleft lip repair. The rate of complete resolution of palatal fistula ranged from 88.6% to 100% in studies with no control group, whereas in comparative studies patients receiving a fat graft showed better outcomes than those not receiving a graft. Evidence suggests that fat grafting can be indicated for the primary and secondary repair of cleft palate, with good results. The use of dermis-fat grafts in lip repair was associated with gains in surface area (11.5%), vertical height (18.5%-27.11%), and lip projection (20%). Fat infiltration was associated with increased lip volume (6.5%), vermilion show (31.68% ± 24.03%), and lip projection (46.71% ± 31.3%). The available literature suggests that fat grafting is a promising autogenous option for palate and fistula repair and for improvement of lip projection and scar aesthetics in patients with cleft. However, to develop a guideline, further studies are needed to confirm whether one technique is superior to the other.

Additive Manufacturing Benchmark 2022 Subcontinuum Mesoscale Tensile Challenge (CHAL-AMB2022-04-MeTT) and Summary of Predictions.

This additive manufacturing benchmarking challenge asked the modelling community to predict the stress-strain behavior and fracture location and pathway of an individual meso-scale (gauge dimensions of approximately 200 µm thickness, 200 µm width, 1mm length) tension specimen that was excised from a wafer of nickel allow IN625 manufactured by laser powder bed fusion (L-PBF). The data used for the challenge questions and answers are provided in a public dataset (https://data.nist.gov/od/id/mds2-2587). Testing models against the data is still possible, although a good-faith blinded prediction should be attempted before reading this article, as the results are contained herein. The uniaxial tension test was pin loaded, conducted at quasi-static strain rates under displacement control, and strain was measured via non-contact methods (digital image correlation). The predictions are challenging since the number of grains contained in the thickness of the specimen are sub-continuum. In addition, pores can be heterogeneously distributed by the L-PBF process, as opposed to intentionally seeded defects. The challenge provided information on chemical composition, grain and subgrain structure (surface-based measurements via electron backscatter diffraction and scanning electron microscopy) and pore structure (volume-based measurements via X-Ray computed tomography) along the entire gauge length for the tension specimen. During the challenge, prediction responses were collected from six different groups. Prediction accuracy compared to the measurements varied, with elastic modulus and strain at ultimate tensile strength consistently over-predicted, while most other values were a mix of over- and under-predicted. Overall, no one model performed best at all predictions. Failure-related properties proved quite challenging to predict, likely in part due to the data provided as well as the inherent difficulty in predicting fracture. Future directions and areas of improvement are discussed in the context of improving model maturity and measurement uncertainty.

Minimally invasive surgical and miniscrew-assisted rapid palatal expansion (MISMARPE) in adult patients.

The purpose of this study was to evaluate maxillary expansion, operative time and pain associated with a new minimally invasive surgical technique to treat maxillary hypoplasia in adult patients. Consecutive patients were included and prospectively analyzed. The technique consists in miniscrew-assisted rapid palatal expansion (MARPE), minimally invasive approach to maxillary osteotomies, latency period and activation period until the desired expansion. The parameters evaluated included operative time, treatment-related pain by the visual analog scale (VAS), and transverse maxillary expansion. The Shapiro-Wilk test was used to assess the normality of data distribution. A paired t-test was used to compare the data between T0 (preoperative) and T1 (postoperative - end of activation). The significance level was set at 5%. Eleven patients were included. Mean operative time was 24.11 min (14.4-32 min) and overall postoperative VAS score was 2.81 (0-9). A comparative analysis showed significant increases in maxillary width at the skeletal, alveolar, and dental levels (p < 0.0001 for all), with a mean range of 1.8 (SD 0.3) mm to 4.7 (SD 0.5) mm. The present minimally invasive surgical MARPE (MISMARPE) technique appears to yield good skeletal outcomes with minimal trauma. It might have potential for clinical use, but larger comparative studies are needed to confirm the clinical relevance of the approach.

Le Fort I osteotomy and soft tissue response: A retrospective cohort study comparing three different techniques.

The aim of this study was to evaluate the nasolabial soft tissues effects in three different Le Fort I osteotomy techniques using cone beam computed tomography (CBCT) evaluation of three-dimensional (3D) volume surfaces. A retrospective study was designed, and three groups were evaluated: group 1, patients who underwent conventional Le Fort I osteotomy; group 2, patients who underwent subspinal Le Fort I osteotomy; and group 3, patients who underwent conventional Le Fort I osteotomy with ANS recontouring or removal. CBCT evaluation was performed at two time points: T0, 1 week before surgery; T1, 6 months after surgery. A total of 90 patients were enrolled in this study (group 1: 30; group 2: 30; group 3: 30). Mean maxillary advancement was 4.26 mm. For group 1, mean change in inter-alar width was 2.29 ± 1.57 mm (minimum -2mm; maximum 6.1 mm; for group 2 it was 1.20 ± 1.56 mm (minimum -1.7 mm; maximum 5.9 mm), and for group 3 was 1.84 ± 1.76 mm (minimum -2.3 mm; maximum 5.9 mm). For group 1, mean change in alar base width was 1.69 ± 2.32 mm (minimum -4.8 mm; maximum 6,1 mm); in group 2 it was 0.85 ± 2.08 mm (minimum -4mm; maximum 6 mm), and group 3 was 1.21 ± 1.83 mm (minimum -2mm; maximum 5 mm). Results showed statistically significant differences in nasolabial area (P < 0.001). Within the limitations of the study it seems that subspinal Le Fort I osteotomy should be preferred when the priority is to avoid changes to the nasolabial region.

Universal scaling laws of keyhole stability and porosity in 3D printing of metals.

Metal three-dimensional (3D) printing includes a vast number of operation and material parameters with complex dependencies, which significantly complicates process optimization, materials development, and real-time monitoring and control. We leverage ultrahigh-speed synchrotron X-ray imaging and high-fidelity multiphysics modeling to identify simple yet universal scaling laws for keyhole stability and porosity in metal 3D printing. The laws apply broadly and remain accurate for different materials, processing conditions, and printing machines. We define a dimensionless number, the Keyhole number, to predict aspect ratio of a keyhole and the morphological transition from stable at low Keyhole number to chaotic at high Keyhole number. Furthermore, we discover inherent correlation between keyhole stability and porosity formation in metal 3D printing. By reducing the dimensions of the formulation of these challenging problems, the compact scaling laws will aid process optimization and defect elimination during metal 3D printing, and potentially lead to a quantitative predictive framework.

Microscale Structure to Property Prediction for Additively Manufactured IN625 through Advanced Material Model Parameter Identification.

Challenge 4 of the Air Force Research Laboratory additive manufacturing modeling challenge series asks the participants to predict the grain-average elastic strain tensors of a few specific challenge grains during tensile loading, based on experimental data and extensive characterization of an IN625 test specimen. In this article, we present our strategy and computational methods for tackling this problem. During the competition stage, a characterized microstructural image from the experiment was directly used to predict the mechanical responses of certain challenge grains with a genetic algorithm-based material model identification method. Later, in the post-competition stage, a proper generalized decomposition (PGD)-based reduced order method is introduced for improved material model calibration. This data-driven reduced order method is efficient and can be used to identify complex material model parameters in the broad field of mechanics and materials science. The results in terms of absolute error have been reported for the original prediction and re-calibrated material model. The predictions show that the overall method is capable of handling large-scale computational problems for local response identification. The re-calibrated results and speed-up show promise for using PGD for material model calibration.

Macroscale Property Prediction for Additively Manufactured IN625 from Microstructure through Advanced Homogenization.

Design of additively manufactured metallic parts requires computational models that can predict the mechanical response of parts considering the microstructural, manufacturing, and operating conditions. This article documents our response to Air Force Research Laboratory (AFRL) Additive Manufacturing Modeling Challenge 3, which asks the participants to predict the mechanical response of tensile coupons of IN625 as function of microstructure and manufacturing conditions. A representative volume element (RVE) approach was coupled with a crystal plasticity material model solved within the Fast Fourier Transformation (FFT) framework for mechanics to address the challenge. During the competition, material model calibration proved to be a challenge, prompting the introduction in this manuscript of an advanced material model identification method using proper generalized decomposition (PGD). Finally, a mechanistic reduced order method called Self-consistent Clustering Analysis (SCA) is shown as a possible alternative to the FFT method for solving these problems. Apart from presenting the response analysis, some physical interpretation and assumptions associated with the modeling are discussed.

[An independent observatory in Vendée on ST-elevated acute myocardial infarction (the OVISCA Register). A Departmental evaluation of demographic trends, mortality and delays before treatment]. / Observatoire Vendéen indépendant des syndromes Coronarien aigus avec sus-décalage du segment ST (Registre OVISCA). Évaluation départementale, évolution démographique, mortalité, délais de prise en charge.

AIM: Mortality from acute myocardial infarction has been falling during the past 30 years. The aim of the study was to evaluate the temporal trends of demographics, mortality rates, and time to treatment in patients admitted for acute ST elevation myocardial infarction (STEMI) in Vendée. PATIENTS AND METHODS: From 2008 to 2016, 1994 patients hospitalised in CHD Vendée for STEMI <48hours were included. Two groups were compared, 838 patients admitted between 2008 and 2011 (group 1), and 1156 admitted between 2013 and 2016 (group 2). RESULTS: Between the 2 periods, mean age was comparable (63.8 vs. 64.4 years), the gender ratio decreased (from 3.15 to 2.79 ; P=0.25). The mean duration of hospital stay was 0.8 day shorter (P=0.008). Treatment at discharge was optimum in 97.5% patients versus 92% (P<0.001). Left ventricular ejection fraction was comparable (50.6% vs. 50.2%). There was a non-significant trend to a decrease in hospital mortality (from 6.3% to 4.4%; p=0.12), and 6-month mortality (from 6.9% to 5.9%; P=0.51). There was a reduction in the use of emergency call-outs (74.9% to 68.9%; P<0.01), but an increase in direct presentations from 44% to 48.7% (P<0.05). The time before calling was comparable (2.5hours vs. 2.3hours; P=04.7). The "door-to-balloon" time decreased (0.71 vs. 0.55hour; P<0.001). The mean time between pain and angioplasty increased (5.7 vs. 6.8hours; P<0.05). CONCLUSIONS: In vendee, from 2011 to 2016, hospital and 6-month mortality of STEMI trend to decrease non-significantly. The door to balloon time decreased, although emergency call-out rates and delays did not. Considerable efforts are still required with respect to patient information and education. Our registry offers an excellent tool to improve practices, the aim being to ensure its integration in the CRAC-France PCI registry.

Indications for fibrinolysis in patients with ST-segment elevation myocardial infarction: From guidelines to practice.

BACKGROUND: European guidelines on managing ST segment elevation myocardial infarction (STEMI) during the first 12hours recommend fibrinolysis when the time elapsing between the first medical contact and balloon time (FMCBT) is more than 120minutes. AIM: To assess the real-life clinical efficacy of guidelines on fibrinolysis in managing STEMI and identify obstacles to their everyday implementation. METHODS: An observational study based on a permanent registry of reperfusion strategies and timing among patients treated in a French general hospital for STEMI with chest pain lasting for less than two hours. Patients were enrolled between January 1st 2008 and December 31st 2014. RESULTS: The study included 669 patients: 79 (11.8%) benefited from effective fibrinolysis followed by coronary arteriography (PCI) within 24hours, 445 (66.5%) underwent a primary PCI, 99 (14.8%) received a rescue PCI and 46 (6.9%) did not undergo revascularization. The FMCBT was 120minutes or longer in 209 patients: fibrinolysis was performed in 68 of these patients (32.5%), and primary PCI in 141 (114 (54.6%) without contraindications to fibrinolysis and 27 (12.9%) with contraindications). The patient's age, female gender, co-morbidities and clinical management were factors that appeared to be linked to poor compliance with the guidelines, but none were significant (P>00.5). Nor were there significant differences regarding bleeding complications between patients receiving fibrinolysis or primary PCI (P>0.05). CONCLUSION: The guidelines on fibrinolysis were not followed in 54.6% of patients when the FMCBT was more than 120minutes. Some criteria (age, gender, co-morbidities) may have been responsible for this non-compliance, although underestimating the time between first medical contact and arrival in the catheterisation laboratory could not be excluded. Further studies are necessary to improve estimates of this delay.

[ST elevation myocardial infarction (STEMI) in patients aged 85 and over. Invasive management versus exclusive medical treatment: Departmental study]. / Syndrome coronarien aigu avec sus-décalage du segment ST chez les patients de 85ans et plus. Prise en charge invasive versus traitement médical exclusif: étude départementale.

INTRODUCTION: Percutaneous coronary intervention (PCI) and/or fibrinolysis for management of an ST elevation myocardial infarction (STEMI) are at high risk in the elderly. Is there any place for an invasive management in this particular population? METHODS: It is a single-center retrospective study (CHD Vendée, La Roche-sur-Yon) including patients aged 85 and over who had STEMI between January 2008 and December 2013, divided into two groups: coronary angiogram/fibrinolysis ("invasive") versus exclusive medical treatment ("non-invasive"), comparing mortality, morbidity, complications and loss of independence. RESULTS: Among the 1373 patients hospitalized for STEMI, 118 (8.6%) were included: 71 (60.2%) underwent an invasive procedure for reperfusion whereas 47 had "non-invasive" management. All cause mortality rate was higher in the "non-invasive" group (28% versus 45%; P=0.077 NS). The identified pejorative criteria are age, female gender, past history of severe valvular disease, and delay for primary care. No difference was found in intrahospital complication rate (23 vs 21; P=0.21) nor in loss of independence. CONCLUSION: The invasive management of STEMI in the elderly may reduce the one-year mortality rate without increasing morbidity.

[Reperfusion delays in acute coronary syndromes with ST segment elevation (STEMI) depending on prehospital care]. / Évaluation départementale des délais de reperfusion des syndromes coronariens aigus avec élévation du segment ST en fonction de la filière de recours aux soins.

INTRODUCTION: Acute coronary syndrome with ST segment elevation (STEMI) remains a major cause of morbidity and mortality in France, directly correlated with the time management of the patient to achieve reperfusion of the artery as early as possible. But the delay of reperfusion is related to the course that will take the patient to the revascularization. METHODS: To make an observation of departmental practices, we conducted a retrospective monocentric study on the STEMI supported on 4years in the Departmental Hospital of La Roche-sur-Yon by comparing the time of reperfusion in two groups: patients who used the recommended chain=diRect chain (Call the emergency number-specialist mobile emergency unit-Cardiac intensive care unit or cardiac catheterization laboratory), and patients who used another chain=Long chain. RESULTS: On 838 patients with STEMI, 356 (42.5%) used the Direct chain. The average time of reperfusion in the Direct chain group is 4.26hours (±3.12), 6.17hours (±4.82) in the Long chain group. There is a significant difference between the two groups of 1.9hours (P<0.001). Of 186 patients who consulted a general practitioner, 40.3% of patients were not supported by the mobile emergency unit. CONCLUSION: These results should lead to improved practices, to carry on continuing medical education with all actors in the chain and patient information to shorten up the time of reperfusion.

[Cardiologic emergencies and natural disaster. Prospective study with Xynthia tempest]. / Urgences cardiologiques et catastrophe naturelle. Étude prospective autour de la tempête Xynthia.

BACKGROUND: Stress-induced cardiomyopathy and ischemic cardiopathy have been described after natural disasters such as earthquakes. OBJECTIVES OF THE STUDY: Count stress-induced cardiomyopathies and ischemic cardiopathies just after Xynthia tempest which damaged the Vendean coast on February2010, in order to study epidemiology. PATIENTS AND METHOD: Included patients were living in a tempest damaged village, and admitted in Vendee hospital just after or in the week following the tempest, and presenting a suspected acute coronary syndrome or stress-induced cardiomyopathy. RESULTS: Among 3350 inhabitants of the two damaged Vendean towns, we count three acute coronary syndromes, two Tako-Tsubo cardiomyopathies, and one coronary spasm. We count five women and one man, average age is 76. CONCLUSION: The diagnosis of ischemic cardiopathy and stress-induced cardiomyopathy is over-represented in this tempest damaged population, that have been little described.

[Care of ST elevated myocardial infarction patients in Vendée in 2008: observational and descriptive study]. / Prise en charge des syndromes coronariens aigus avec sus-décalage du segment ST en Vendée en 2008: étude observationnelle descriptive.

PURPOSE OF THE STUDY: Estimating the quality of care of the patients presenting an ST-elevation myocardial infarction in Vendee. PATIENTS AND METHOD: Prospective observational study carried out over the year 2008. Included patients presenting a myocardial infarction for less than 24 hours, they were alive when emergency team arrived, and were taken care of by the SMUR, the emergencies or the cardiology of the hospital of La Roche-sur-Yon. RESULTS: Two hundred and seventeen patients were included, 163 men and 54 women, average age: 65 years. Fifty-six percent of the patients called initially the emergency medical service, half of those within an hour after pain began. Seventy-two percent of them were looked after by a SMUR. Twenty-six percent consulted initially a general practitioner, and one third of those were redirected towards the emergency medical service. Thirty percent of all patients followed the ideal procedure defined by succession of chest pain, emergency medical service call, SMUR, angioplasty or fibrinolysis. The average time between the ECG and the fibrinolysis is 36 minutes, or of the arrival in coronarography room is 105 minutes. The balloon is inflated 42 minutes later. Eighty-six percent of the patients taken care of in the acute phase benefited from a strategy of reperfusion, primary angioplasty (63%) or fibrinolysis (21%). Ninety percent of revascularisations were successful. CONCLUSION: In the case of the chest pain, the emergency medical service is under-used. The number of revascularised patients is satisfactory, but the whole procedure takes too much time, especially when the treatment is the angioplasty.

[Coronary embolism: a not so rare cause of myocardial infarction? Review of the literature about five suspected cases of patients in atrial fibrillation]. / Infarctus du myocarde par embolie coronaire: pas si rare que cela? Revue de la littérature à propos de cinq observations de patients en arythmie complète par fibrillation auriculaire.

Five cases of myocardial infarction suspected to be due to coronary embolism are presented. All five patients had atrial fibrillation (AF), four of them with nonvalvular AF. The literature regarding coronary embolism is reviewed; the clinical manifestations and the place of AF are discussed.

[Non-ruptured calcified aneurysm of the Valsalva's sinus with angina pectoris and aortic insufficiency. Surgical treatment]. / Anévrysme calcifié non rompu du sinus de Valsalva avec angor et insuffisance aortique. Cure chirurgicale.

We report a case of aneurysm of the straight frontal, and not coronary, aortic sinus, non ruptured and calcified, responsible for a refractory angina pectoris and a massive aortic failure in a 71 year old woman. The surgical treatment consisted in the exclusion of the aneurysm of the aortic sinus by a tubular prosthesis in which only two thirds of the circumference have been used, associated with the replacement of an aortic valve by a bioprosthesis, without associated coronary by-pass.